In September, it was Ruslan B. Yamadayev, shot while his car was stuck in Moscow traffic. In January, a former Kadyrov bodyguard named Umar S. Israilov was shot in Vienna when he stepped out to buy yogurt. Then, last week, Sulim B. Yamadayev — a brother of Ruslan’s — was shot in the parking garage of his apartment complex in Dubai, United Arab Emirates.

This time, though, something unusual happened: Dubai’s police chief called a news conference and publicly excoriated Russian authorities for allowing the violence to continue.

The allegations pose a problem for leaders in the Kremlin, who installed Mr. Kadyrov as president of Chechnya and have relied on him to stamp out an insurgency that threatened to wrest the republic from Moscow’s control.

While prime minister and now president, Mr. Kadyrov has virtually eliminated the insurgency; human rights organizations and journalists have documented his regime’s use of brutal tactics, among them abduction and torture.

Authorities in Moscow apparently put few restraints on Mr. Kadyrov. And on Monday, as the accusations against Mr. Delimkhanov made headlines, observers wondered whether Russian leaders were willing, or able, to do so.

“They need him,” said Mark Galeotti, an expert on Russian crime at New York University’s Center for Global Affairs. “They’ve actually created a kind of Frankenstein’s monster. In the name of fighting Chechen nationalism, they’ve basically created an autonomous Chechen state.”

Sulim Yamadayev, the man killed in Dubai, was once a powerful Chechen military commander and had posed an increasing threat to Mr. Kadyrov.

After a clash between his troops and Mr. Kadyrov’s guards last year, federal authorities stripped him of his command and he left Russia for Dubai in December. Mr. Kadyrov’s government has denied responsibility for that clash.

Russian federal authorities have made no comment on the Dubai case. Because Mr. Delimkhanov was elected last year to Parliament, he has immunity from prosecution, and Russian law does not allow its citizens to be extradited.

An official in the general prosecutor’s office said Sunday that Russia would prosecute him if Dubai police provided convincing evidence.

“I must say that Adam Delimkhanov is my close associate, a friend, a brother or even my right hand,” Mr. Kadyrov said in a statement. “I take any statements concerning him personally. We will take all measures provided by Russian and international laws to hold responsible those who make slandering insinuations.”

In comments to reporters in Grozny on Monday, Mr. Kadyrov said that Sulim Yamadayev had repeatedly tried to assassinate him, at one point by poisoning a lake.

He also said there was “objective evidence” that implicated Mr. Yamadayev in a 2004 bombing that killed his father, Akhmad Kadyrov, who was then the president of Chechnya.

“We did all that we could to bring Sulim Yamadayev, who was involved in a series of killings, kidnappings and other severe crimes, to trial in Russia,” Mr. Kadyrov said, according to the news agency Interfax.

The scandal comes at a difficult moment for Russia’s president, Dmitri A. Medvedev, who has vowed to make rule of law the foundation of his presidency. It also coincides with a much-discussed “reset” of relations between Russia and the United States, as Western leaders set aside, at least for the moment, criticism of human rights abuses in Russia.

Sergei Markedonov, head of the interethnic relations department at the Institute of Political and Military Analysis in Moscow, said that he was not convinced that Mr. Kadyrov had ordered the murder, but that the case had already raised “a lot of unpleasant questions for Russia as a whole and for Medvedev.”

“Why was Ruslan Yamadayev killed, and then Sulim Yamadayev?” Mr. Markedonov asked. “Why is there no opposition to Kadyrov? What is this regime that Moscow supports? And to what extent is Moscow able to influence it?”

Hints of a shift in the relationship came after Sulim Yamadayev died on March 31. That day, the Kremlin had seemed prepared to grant Mr. Kadyrov’s longstanding request to withdraw thousands of federal troops from Chechnya. The act would remove shipping and transportation restrictions imposed as part of a counterterrorist operation when the second Chechen war began nearly a decade ago.

Less than a week later, however, as news of Mr. Yamadayev’s death began to circulate, Russia’s National Antiterrorist Committee announced that the restrictions and troops would remain in place, citing a continuing danger of violence in the region. Officials said the murder had nothing to do with the committee’s decision.

“It does appear that at this point in time the Kremlin does want to keep some control over Kadyrov and his team,” said Tatyana Lokshina, a Chechnya expert with Human Rights Watch in Moscow. “Ending the counterterrorist operation, getting multitudes of troops out and removing all the restrictions would give Kadyrov even more freedom — and he certainly does have enough.”

But in recent years, she added, Moscow has made little attempt to interfere with Mr. Kadyrov’s tactics, “as long as he kept the insurgency suppressed.”

With Kremlin backing, Mr. Kadyrov has accomplished in just a few years what few independent experts thought would be possible in decades. He has winnowed the insurgency by killing off most of the rebel leaders and granting amnesty to militants in exchange for loyalty. Chechnya’s capital, Grozny, has been largely rebuilt. Cafes and restaurants are bustling, electricity is more or less regular and people stroll along newly built avenues.

“They built up Kadyrov, and from their point of view, he’s doing what he is supposed to be doing,” Mr. Galeotti, of N.Y.U., said. “Considering the rise of chaos in the rest of the North Caucasus, the irony is that Chechnya is a haven of peace.”

International attention has drifted away from Chechnya since then. Mr. Markedonov, a specialist in the north Caucasus, said he had not heard the republic discussed so avidly in the international news media for years.

He compared the Yamadayev case to the furor that resulted in 2007 when British authorities pressed Russia to extradite Andrei K. Lugovoi, a former K.G.B. agent, in the killing of a former spy, Alexander V. Litvinenko, who died in London after ingesting polonium 210, a rare and toxic radioactive isotope.

“Already, in our media,” Mr. Markedonov said, “they have started to call it ‘Litvinenko 2’ or ‘Lugovoi 2.’ ”

A version of this article appears in print on , on page A5 of the New York edition with the headline: Killings of Chechen Leader’s Foes May Test Kremlin’s Will or Power to Restrain Him. Order Reprints|Today's Paper|Subscribe